The DELTA Group (DELTA stands for Detection and Evaluation of Long-range Transport of Aerosols) is an air quality group comprised of west coast scientists based out of UC Davis that have published a number of studies regarding "aerosol and climate studies", with a seeming focus on local micro pollution and the development of technologies to better measure air quality. The director of the group is Dr. Thomas A. Cahill, Department of Applied Science; Department of Land, Air and Water Resources; Department of Chemical Engineering and Material Sciences; and Department of Physics, University of California, Davis.

Notably, they did assessment of World Trade Center samples after they were destroyed on 9/11, 2001. They also discovered a 1 in 1,000 increase in cancer at the Roseville railroad switchyard that resulted in changes. They have also done studies of Watt Road in Sacramento.

They are currently proposing/doing a study of the impact of fireplaces, tied to the wood burning ban. They have asked people to report smoke in your neighborhood by calling the Public Works Department at 530-757-5686 or the air quality district at 800-246-3660, or report online by using the Citizen Request Manager. Provide the location of smoke, date and time it was detected, speed and direction of wind, the look and smell of the smoke, and the possible source. This is to help with the data collection, and using a fireplace is not illegal (yet), so proponents say you should not think of this as snitching.